‘Animal culture’ reshapes ideas about evolution

Monday 24 July 2017

Culture was once thought to be what distinguishes humans from other animals. However, research by academics from the University of St Andrews studying animal behaviour tells a radically different story.

A special edition of the Proceedings of the National Academy of Sciences of the USA, The Extension of Biology through Culture, published this week, features a new collection of articles by University of St Andrews scientists researching animal culture and behaviours. Research concludes that discoveries about the widespread occurrence of all kinds of cultural traditions in animals mean that our broader understanding of how evolution works needs to be extended in substantial and fascinating ways.

Based on a conference at the Academy led by Professor Andrew Whiten of the School of Psychology and Neuroscience and Professor Kevin Laland of the School of Biology, in collaboration with Professors Francisco Ayala and Marc Feldman in the USA, St Andrews scientists contribute no less than three different articles to the collection. An introductory article by Professor Whiten and colleagues also details the new picture of animal culture emerging and its implications for evolutionary biology at large.

Cultures passed on by learning from others have now been reported in hundreds of studies of animals as diverse as apes, whales, birds and bees. This research has focussed on cultural learning and how it affects numerous aspects of animals’ lives from how to find food, to avoiding predators, communicating with others, choosing a mate, setting up home or migrating. All this amounts to a second form of inheritance, based on learning from others, that allows behaviour to evolve in ways beyond those that have been prominent in mainstream evolutionary thinking, based on genetic inheritance. This cultural channel of inheritance allows animals to adapt to their environments in faster ways than genetic change can manage.

Adaptation led by cultural change may in turn shape genetic evolution. For example, different populations of killer whales have developed very different hunting traditions focused on either fish or seals, which is thought to have led to corresponding changes in their jaws to suit their preferred prey.

Song cultures of whales

Dr Ellen Garland and Dr Luke Rendell, School of Biology

In an earlier study, Dr Ellen Garland from the University of St Andrews and colleagues discovered an extraordinary cultural phenomenon in the songs of humpback whales. Around Australia, some new songs would emerge and quickly become popular, being shared by all nearby whales. This new song would then be transmitted eastwards across the South Pacific Ocean, travelling right across to French Polynesia over the next year. In later years, more songs followed in this way, passing in waves across the ocean. Now, Dr Garland, Dr Rendell and their colleagues have been able to track exactly how the change from old to new songs occurs, revealing details of how evolution works within such animal cultures.

The team investigated rare cases of song hybridisation, found among thousands of hours of song from the South Pacific, where parts of an existing song were spliced with a new one, and likely prior to an individual whale totally adopting the new song. The team unearthed two different kinds of structural rules guiding song change. In one, a whale sings some of the old and some of the new song, making a transition between them with a kind of short hybrid ‘phrase’. In the other approach they may splice into their current song a whole ‘theme’ from the new song others are beginning to sing.

Dr Ellen Garland from the University of St Andrews said: “These rare glimpses into the underlying learning mechanisms show that songs appear to be learnt as segments, reminiscent of the way children acquire language.”

Tradition and ‘cultural intelligence’ in the great apes

Professor Andrew Whiten, School of Psychology and Neuroscience

Recent studies by primatologists from the University of St Andrews and others across Europe, concentrating on the great apes, suggest that these animals have the richest cultural profiles identified so far amongst animals.

Now, following new behavioural experiments with chimpanzees, research suggests that these apes may indeed share some of the foundations of our remarkable cultural nature. Professor Whiten and his team have shown that great apes pass on such traditions and even extend them.

Professor Whiten explains how such findings have led to the hypothesis that a key factor in explaining ape intelligence and their larger than average brain may be the complexity of their cultures. This is the ‘cultural intelligence hypothesis’ that ‘culture makes you smart’, as is so clear in our own species.

Dr Sally Street, School of Psychology and Neuroscience, and Professor Kevin Laland, School of Biology

Dr Sally Street, Professor Kevin Laland and colleagues took these ideas further and tested them across a large sample of 184 different species of primates.

Applying sophisticated new methods of statistical comparison, the authors find that measures of the proclivity for social learning in a species predicts both their absolute and relative brain size, as well as their typical longevity and group size. These findings suggest either that greater reliance on culture has driven increases in brain size in the primate order to which we belong, or that cultural complexity and genetically based ‘braininess’ have grown in a co-evolutionary spiral: an example of the ways in which the importance of culture extends our understanding of evolutionary biology for both our own and other species.

Those species of primate most reliant on culture were also found to have longer lifespans and to live in larger social groups. Dr Street and colleagues conclude that the evolution of large brains, sociality and long lifespans have promoted reliance on culture, with reliance on culture in turn driving further increases in brain size, cognitive abilities and lifespans in some primate lineages.

PNAS is one of the world's most-cited and comprehensive multidisciplinary scientific journals, publishing more than 3100 research papers annually. Established in 1914, PNAS publishes cutting-edge research, science news, commentaries, reviews, perspectives, colloquium papers, and actions of the National Academy of Sciences.